THE BUG MAN: Watch Out for Aloe Thrips
- 19 hours ago
- 3 min read
By Eric Middleton PhD, IPM Advisor, University of California Statewide IPM Program and Cooperative Extension, San Diego, Orange, and Los Angeles Counties, for Let’s Talk Plants! September 2026.
Watch Out for Aloe Thrips
If you live in Southern California and your aloes are darkening and starting to die back, it could be caused by a new invasive pest called aloe thrips (Hercinothrips dimidiatus).
Aloe thrips is an invasive thrips species that was recently confirmed to be present in San Diego, Ventura, and Santa Barbara counties in early 2026. This was the first documented case of aloe thrips in North America, and previously it had only been observed in South Africa and parts of Europe with a Mediterranean climate.
Aloe thrips feed on the surface of aloe leaves causing black spots and heavy scarring that eventually starts covering the entire leaf (Figure 2a and 2b). As damage progresses, aloe leaves turn black or bronze and sections of the aloe begin to wither away completely (Figure 2c and 2d). In San Diego County, numerous landscape aloes are dying back and often being killed outright from damage caused by these thrips. Aloe thrips are mostly known to feed on Aloe arborescens, Aloe vera, and hybrids of either of these species, but there is also a lot we don’t know about this pest, so keep an eye out on any aloes you have.
Figure 1. a) Early signs of aloe thrips damage where scarring and black spots become visible; b) A closer view of scarring and blackening caused by aloe thrips; c) Heavy aloe thrips damage characterized by significant scarring and blackening of leaves; d) Dieback caused by aloe thrips as entire sections of the aloe plant turn black, wither, and die.
The thrips themselves are very small, but pretty distinctive if you run into them. Adults are slender dark insects around 1 mm long with 3 visible whitish bands on their backs and are often found near the crown of the aloes (Figure 2a and 2b). They are hard to spot even under ideal conditions, so magnification and some patience will help a lot. Immature aloe thrips are shiny and almost wet-looking with red, brown, and pale coloration (Figure 2c). They also usually have drops of dark liquid feces hanging on the tip of their abdomen, and you can see shiny flecks of this feces when it dries on the surface of the aloe leaves as well.
Figure 2. a) A group of adult aloe thrips seen without magnification on the surface of an aloe leaf; b) Magnified adult aloe thrips where 3 horizontal light bands are visible on their wings; c) Magnified immature aloe thrips with a shiny appearance and droplets of feces on their abdomens.
When it comes to management, getting rid of heavily infested and damaged plants is probably the best course of action. We don’t currently know what control methods work best for this pest, so keeping infestations from spreading is key. If additional control is necessary, a foliar application of spinosad is likely a good option since it is effective against many thrips species and is available to both professionals and members of the public (but again, we don’t have any data on how effective various methods are yet!).
Because aloe thrips was only found here recently, we’re still trying to figure out where all it is in California and we could use your help. If you run into Aloe arboresecens or Aloe vera that is blackening and dying back and especially if you also see striped thrips on the plant, please let us know! Note the location, take some pictures and email them to aloe.thrips@gmail.com and we’ll verify if it looks like aloe thrips damage. You can also reach out to Eric Middleton directly at egmiddleton@ucanr.edu. This is especially useful to us if you are anywhere in the US outside of San Diego, Ventura, or Santa Barbara Counties, since aloe thrips hasn’t been confirmed outside of these three counties. Let us know, and together, we can track this new invasive pest and hopefully come up with better management solutions shortly!
